Mobile bodies such as robots that provide various services in real environments where there are people such as offices and factories are being developed, with development of such robots being premised on the robots moving autonomously to a destination while avoiding obstacles. Non-patent Literature 1 discloses an artificial potential field approach regarding obstacle avoidance. According to this artificial potential field approach, an attractive potential for the destination and repulsive potentials for obstacles to be avoided are generated, and control is implemented according to the gradients of the potential field on which these potentials are superimposed. Traction motors are driven in accordance with this control, and the mobile body arrives at its destination while avoiding obstacles.
When avoiding obstacles, the mobile body desirably avoids the obstacles smoothly without taking a long way around. Obstacles occur in areas other than walls and pillars such as passageways and the like through which the mobile body is capable of passing, although those areas are not always wide enough. In view of this, it is desirable that obstacles are smoothly avoided, that is, that if there is a gap through which the mobile body is able to pass by changing its orientation, the mobile body will pass through even a narrow gap and take smooth evasive action. However, since most research to date has involved searching for a movement path using models approximating a mobile body to a circle, no consideration whatsoever has been given to changing the orientation of the mobile body. In other words, with existing techniques that approximate a mobile body to a circular model, a circular model that completely contains the long side of the mobile body is configured even if the mobile body is elongated in plan view, and therefore a gap through which the mobile body could pass if it were to move forward with its short side facing the front will be determined to be impassable, resulting in the mobile body avoiding obstacles by taking a big detour.